In 2013, for the first time, solar installations exceeded wind. The margin was narrow, about a gigawatt, but the development has set off some interesting predictions. One of these, from US-based analyst Clean Edge, forecasts that by 2021 global cumulative installed solar photovoltaic (PV) capacity will overtake that of wind. At present the cumulative installed capacity of wind is about two and half times greater than that of PV. For Clean Edge's prediction to come true, the cost of PV-generated energy will need to continue to fall to compete with wind on a global basis. One of the biggest contributing factors to PV generation growth has been the sharp reduction in the cost of crystalline silicon PV modules, which have seen prices fall by more than 65% in the past three years to less than $1,000/kW (EUR 700/kW). Solar PV is now delivering low-cost electricity in a range of ...